Factor V Leiden mutation investigated by amplification created restriction enzyme site (ACRES) in PNH patients with and without thrombosis.

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired chronic hemolytic anemia characterized by intravascular hemolysis, often associated with neutropenia and thrombocytopenia. Venous thrombosis, including the Budd-Chiari syndrome, is one of the major complications of PNH, but not all PNH patients develop thrombosis. The basis for the high risk of thrombosis in PNH is not known. Recent reports have shown that Factor V Leiden mutation is a common cause of increased tendency to develop thrombosis. Fifty-six PNH patients were tested for Factor V Leiden mutation using Amplification Created Restriction Enzyme Site methods. PNH patients do not show an increased frequency of Factor V Leiden mutations.